Optical measurement devices are used in a variety of different applications. Optical measurement devices include devices that are used to measure or otherwise determine one or more properties of light such as intensity, colour, wavelength, or other characteristics. One type of optical measurement device is an optical density sensor. One type of optical density sensor is a cell density sensor which operates by shining light through a solution to a receiver. The optical density of the solution changes the amount of absorption or scattering of the passing light. The light receiver outputs a signal dependent on the intensity of the light received, which is in turn dependent on how much scattering or absorption the solution has caused.
Cell density sensors are used in biotechnology, chemical, brewing, wine making, fermentation, pharmaceutical, and other sectors of industry or research. For biotech applications, cell density sensors are ordinarily used to monitor growth of living cells in a cell culture.
A disadvantage with such optical measurement systems is that they typically require an onerous process in order to be used. The process includes repeated removal of a sample of the solution at consecutive time points under sterile conditions, applying that sample to a measurement device, recording the measurement and disposing of the sample. This process increases the risk of contamination, and the loss of sample volume from the solution.
It is an object of the present invention to provide an improved measurement system which overcomes or at least ameliorates some of the abovementioned disadvantage or which at least provides the public with a useful choice. Other objects of the invention may become apparent from the following description which is given by way of example only.